Nigel_ Posted at 2017-8-27 13:58
Although you were running very low on battery, and the battery % figure was very inaccurate, the actual reason it fell out of the sky was that your ultrasonic sensors thought that it had landed on something, you then pulled the throttle full down as you do when you land to cut the motors and a few seconds later it cut the power to the motors since it thought they were no longer needed.

Do you have a gimbal guard or something mounted under the aircraft that it could mistake for the ground?

Hmmm i do have a gimbal guard underneath the gimbal.

Nigel_ Posted at 2017-8-27 13:58
Although you were running very low on battery, and the battery % figure was very inaccurate, the actual reason it fell out of the sky was that your ultrasonic sensors thought that it had landed on something, you then pulled the throttle full down as you do when you land to cut the motors and a few seconds later it cut the power to the motors since it thought they were no longer needed.

Do you have a gimbal guard or something mounted under the aircraft that it could mistake for the ground?

OK, I know you are a Guru with this stuff...but tell us your secret, please?  How did you determine what you did with respect to the UAV thinking it was landing, and then the gimbal guard (I assume that was deductive reasoning)...what's your magic?  
Please share...

Thanks!

wormz30 Posted at 2017-8-27 14:32
Hmmm i do have a gimbal guard underneath the gimbal.

Well there goes any chance of a warrantee claim, fairly certain that was the explanation.

Which firmware did you have installed?  Thread title suggests the latest update but I haven't seen one fall from that height due to a gimbal guard for some time...

wormz30 Posted at 2017-8-27 09:15
Welp... @Geebax, @Alabama, @labroides, here it is... I found a perfect thread to support what you guys were talking about.
https://forum.dji.com/thread-51147-1-1.html

4/ bow to Geebax
Bowing is not necessary, a simple genuflection will be sufficient. The reason for the brief reply is that I am flat out on my back in hospital after having the Terminator Special Titanium Spine job. It has taken me nearly 3 minutes to type this far. For that reason, i am being more economical than usual. Sorry about the silly bit, that was a bit cruel.

@nigel. I wasn't landing though. I was bringing it back home. It was still 680 feet away from home. I don't recall trying to bring it down from that distance

Geebax Posted at 2017-8-27 15:19
4/ bow to Geebax
Bowing is not necessary, a simple genuflection will be sufficient. The reason for the brief reply is that I am flat out on my back in hospital after having the Terminator Special Titanium Spine job. It has taken me nearly 3 minutes to type this far. For that reason, i am being more economical than usual. Sorry about the silly bit, that was a bit cruel.

Geebax, you're being wayyyy to nice.  Has to be the morphine lol  (just kiddin)

wormz30 Posted at 2017-8-27 15:27
@nigel. I wasn't landing though. I was bringing it back home. It was still 680 feet away from home. I don't recall trying to bring it down from that distance

About 13 seconds before the end of the log, you were going flat out forward and then started pulling the throttle down to descend.  Doesn't mean that you were landing, just lowering the altitude while still going full forward.

I'm still wondering why it allowed the motors to power off at that altitude, if it was the new firmware, did you have landing protection turned on?

Also, maybe you could give the gimbal guard manufacturer some publicity so that people know how good their gimbal guard is at protecting the gimbal from being damaged!  Then you might try to claim some compensation off them, at least the price of the gimbal guard.

quadpilot Posted at 2017-8-27 15:23
hi nigel
i have been landing the craft with brand new batteries at around 47 to 50 % charge left in them
should i fly them to just over 30% say 35% to start with ?

For a new battery, I would take it down to 30% a couple of times, and then take it down to the 10% critical landing once, otherwise it can't learn what happens in the lower part of the range. Don't know what algorithms it actually uses so cant be exact.  After that use it however you like.

If you want to be cautious, go into the settings and turn on the voltage display. Then for new batteries make sure it doesn't drop below 4v per cell.  As above, empty is around 3.3v per cell but you don't really want any of the cells getting that low.

The batteries are pretty reliable as long as you always charge them fully no more than 24 hours before use. I've never had any issue using them for multiple flights without recharging, even taking off at 20%, but I would only do it if they are all the same day.

Genghis9 Posted at 2017-8-27 14:45
OK, I know you are a Guru with this stuff...but tell us your secret, please?  How did you determine what you did with respect to the UAV thinking it was landing, and then the gimbal guard (I assume that was deductive reasoning)...what's your magic?  
Please share...

"what's your magic?  "
You need to analyse the logs like Mr Spock would

Geebax Posted at 2017-8-27 15:19
4/ bow to Geebax
Bowing is not necessary, a simple genuflection will be sufficient. The reason for the brief reply is that I am flat out on my back in hospital after having the Terminator Special Titanium Spine job. It has taken me nearly 3 minutes to type this far. For that reason, i am being more economical than usual. Sorry about the silly bit, that was a bit cruel.

Dude sorry to hear this!!!  We'll pray that all goes well in your recovery, please take care.  I'd say rest, but I'm assuming if you are making such an effort to comment here, it must be serving as a distraction.
Take Care God Bless!

Genghis9 Posted at 2017-8-27 16:36
Dude sorry to hear this!!!  We'll pray that all goes well in your recovery, please take care.  I'd say rest, but I'm assuming if you are making such an effort to comment here, it must be serving as a distraction.
Take Care God Bless!

Thank you for your kind wishes, and yes, you are spot on, it is a welcome distraction.

ALABAMA Posted at 2017-8-27 15:43
Geebax, you're being wayyyy to nice.  Has to be the morphine lol  (just kiddin)

Oh yea, the drugs - mmmm drugzzzzzzzz.

@nigel_ BALLS... you're right. I did have my throttle down to lower altitude.

So basically at this point... I need to weigh my options:

a) get a refurbished P4 for $799 because DJI is not going to repair this thing for free + I have two healthy batteries already
b) get a refurbished Mavic Pro for $799 and sell my two batteries and radio for $250-300 and pick up two more mavic pro batteries
c) save up and get P4P
d) Screw it. I'll stick to my DJI Spark

What say you?

Nigel_ Posted at 2017-8-27 16:17
"what's your magic?  "
You need to analyse the logs like Mr Spock would

Well Spock...I'll leave it at that, even if you tried to explain it to me I'd likely have trouble learning it all.  Maybe in time I'll get to know this stuff, for now it's better that I focus on the basics.
I will stand to live & learn from you as we go along
Live Long & Prosperous!

wormz30 Posted at 2017-8-27 17:19
So basically at this point... I need to weigh my options:

a) get a refurbished P4 for $799 because DJI is not going to repair this thing for free + I have two healthy batteries already

As you have a Spark, I wouldn't bother with a Mavic, the advantage of the Mavic is that it is portable, but the Spark does that much better!  The Mavic camera doesn't have the quality of a P4.

It has to either be a P4 (refurbished or body only) or a P4A/P4P.  Can you use a body only P4A with your existing remote?

Depends on if you want that 1" sensor in the camera with 4K 60fps or are happy with the smaller P4 sensor.  The 1" sensor has a clear advantage for raw photography and low light videography, but if you only use it for video in sunlight then you wont see a huge difference.

Genghis9 Posted at 2017-8-27 17:28
Well Spock...I'll leave it at that, even if you tried to explain it to me I'd likely have trouble learning it all.  Maybe in time I'll get to know this stuff, for now it's better that I focus on the basics.
I will stand to live & learn from you as we go along
Live Long & Prosperous!

There is not really a lot to explain, the data is all there in the logs, you just need to work it out with a bit of logic, the answer is different for each event so I can't teach you the answer right now.  Even experts like Geebax and Labroidies who know how to look at the logs didn't see that there was a gimbal guard attached and pretending to be the ground - there are not many people about who think like Mr Spock, but that is the way to find the real answer!

OK, Guys!  It was verry interesting reading this discussion.
To add my experience with absolutely no intention to put any advice on it.
I have been flying my P3A near 3 years now. I had 2 incidents caused by my mistake only, otherwise I fly with no problems.
Often I start the short fly with 60% of battery for instance (not less because the phantom would not go up and give low battery warning.
In such short flights I drained the batteries to under 30% with no problems.
And another thing I noticeed in your posts : almost every crash happened after updating the firmware! Do this tells you something?

andy10 Posted at 2017-8-28 02:00
And another thing I noticeed in your posts : almost every crash happened after updating the firmware! Do this tells you something?

Yes, that tells me that DJI released a firmware update recently, lots of people installed it and then flew their aircraft, as a result most of the recent crashes have happened after people have updated the firmware.  

What it does not imply is that the firmware is responsible for the crashes, only that people have recently updated the firmware.

In any case, we don't know which firmware was installed for this crash, since I asked twice and didn't get an answer it seems quite likely that this was not the latest DJI firmware.

Computers carry out Programmed instructions.

When the battery is low, the drone returns to home.
When the battery is at critic level, it hands.

If you try take off with a half full, or any level of battery, all the above rules still remain and those actions will be carried out as the rules are based upon the Cell Voltages being monitored in real-time.

Operator Error DOES NOT even come into this. A drone going crazy is a malfunction, and this latest Firmware is full of issues. This is a fact.

Sorry Nigel I have the latest firmware

Wait up. It's supposed to be 2.0 as of July right...? I got the firmware update in July. I went through the process and everything... why does it say 1.8?

And Nigel. I was thinking about how you said it could've dropped out because I held down the throttle, but I had done a flight just moments before that and it didn't drop out of the sky like that. So I'm not sure if he gimbal guard was the culprit. Hell of a theory though

Wait. Yeah. I just checked my dji go4 app and it says I have the latest firmware. 1.8 for this drone is the latest so I'm not sure what 2.0 is according to dji

I just took a screenshot of what I got when I fired up the updated app and everything. Not sure what this is about but I clearly remember going through the update in July.

wormz30 Posted at 2017-8-28 06:17
And Nigel. I was thinking about how you said it could've dropped out because I held down the throttle, but I had done a flight just moments before that and it didn't drop out of the sky like that. So I'm not sure if he gimbal guard was the culprit. Hell of a theory though

It only cuts the motors if you pull the throttle full back, also the gimbal guard wasn't blocking the sensors 100% of the time so my guess is that it's position had slipped a little since the last flight, is it just clipped on and can move?

Thanks for the firmware info, my other question was did you enable landing protection?  Reason I ask is that although you pulled the throttle full back, the aircraft did not descend making it look like it was actually on the ground.  Presumably the reason it didn't descend was that it could see that it was on the ground (incorrectly).  Just wondering if the safeguard that checks that it is not falling before cutting the motors may have been rendered useless by the new landing protection feature that prevents it falling if a gimbal guard blocks the ultrasonic sensors...

It's clipped on and it's on there like a rock. no way it would get rocked and reposition itself. When it crashed it was in the same spot it was before. as a matter of fact, it looks like it even took a hit and didn't move... as for the landing protection, I don't know where to check for that. It doesn't show in the app as an option. Is that a thing for phantom 4?

wormz30 Posted at 2017-8-28 06:51
It's clipped on and it's on there like a rock. no way it would get rocked and reposition itself. When it crashed it was in the same spot it was before. as a matter of fact, it looks like it even took a hit and didn't move... as for the landing protection, I don't know where to check for that. It doesn't show in the app as an option. Is that a thing for phantom 4?

Did the gimbal guard save the gimbal during the crash?

Landing Protection is one of the new options with the new P4 firmware, it is an on/off option somewhere in the setup...  think the default is off which may or may not work the same as before...

It looks like it landed in an angle and hit the corner of the curb. Shoved the gimbal right into its casing lol. So no

And that's what I don't get. It says I have the latest firmware but I'm on 1.8 even though in July there was a 2.0... am I just going crazy?

wormz30 Posted at 2017-8-28 08:26
And that's what I don't get. It says I have the latest firmware but I'm on 1.8 even though in July there was a 2.0... am I just going crazy?

Have you plugged it into a PC and used DJI Assistant to check for available updates?

Hmmm didn't know that was even an option. I figured if the iOS app has an update, go update. If there's a new firmware, go and download it. Otherwise I'm good. No?

TN Lone Wolf Posted at 2017-8-27 06:13
I'm also interested in the answers to Genghis9's questions.  I've flown my fair share of flights with non-fully charged batteries with no issue, nor have we had any issue with my university's Inspire or Mavic.

TN Lone Wolf
I guess Labroides took a pass on those questions.
However, if you read through this thread https://forum.dji.com/thread-51147-1-1.html you will become fairly well informed on the topic and find several if not all the answers to the questions I asked.  This link actually comes from post #37 here.  Either way it leads to some good stuff, also in this other thread there is yet another link to another thread that has some additional info, suggest you read that one too.  If you read them both I believe you will learn what you want on this subject.
As to the last question (#4) and why it did not initiate a RTH/Auto Land, I believe Nigel may have hit on the answer near the bottom of this thread, may have something to do with using a gimbal guard.
Enjoy!

wormz30 Posted at 2017-8-27 17:19
So basically at this point... I need to weigh my options:

a) get a refurbished P4 for $799 because DJI is not going to repair this thing for free + I have two healthy batteries already

I would recommend you to contact our Support Team via support.us@dji.com to report the case.
You can make the decision after the corresponding solution was offered.

Nigel_ Posted at 2017-8-28 06:41
It only cuts the motors if you pull the throttle full back, also the gimbal guard wasn't blocking the sensors 100% of the time so my guess is that it's position had slipped a little since the last flight, is it just clipped on and can move?

Thanks for the firmware info, my other question was did you enable landing protection?  Reason I ask is that although you pulled the throttle full back, the aircraft did not descend making it look like it was actually on the ground.  Presumably the reason it didn't descend was that it could see that it was on the ground (incorrectly).  Just wondering if the safeguard that checks that it is not falling before cutting the motors may have been rendered useless by the new landing protection feature that prevents it falling if a gimbal guard blocks the ultrasonic sensors...

Nigel,
Need some help here, I've read this post a couple of times and I can't quite figure it out.
Specifically, the last sentence of the 2nd paragraph.  Can you explain this more please?  I don't know enough to understand how or why landing protection on or off defeats this other feature of falling you are referring to.
Thanks

Genghis9 Posted at 2017-8-28 23:37
Nigel,
Need some help here, I've read this post a couple of times and I can't quite figure it out.
Specifically, the last sentence of the 2nd paragraph.  Can you explain this more please?  I don't know enough to understand how or why landing protection on or off defeats this other feature of falling you are referring to.

It appears to be irrelevant since wormz doesn't appear to have the latest firmware and thus has no landing protection.  Possibly if the new firmware was installed then there wouldn't have been a problem.  When the P4 first came out there where a number of incidents with gimbal guards, more recently the problem appears to have been more or less solved so I was surprised to see this.

We haven't seen any images of the damage, maybe it can be repaired?

@Nigel_ from what i've assessed of the the damage, the gimbal needs to be replaced for sure. one of the ccw motors needs to be replaced, landing gear, and shell need to be replaced. Also, I've had the gimbal guard for a long while so I don't think the gimbal guard would have anything to do with it. Even just holding down the throttle from up high lol, otherwise I wouldn't have ever been able to land. However, a few months ago, i did send my P4 into DJI and (after several weeks) they sent me one back so who knows? Maybe that is the culprit?

Doesn't look like theres a DJI assistant for mac for P4.

Nigel_ Posted at 2017-8-28 23:51
It appears to be irrelevant since wormz doesn't appear to have the latest firmware and thus has no landing protection.  Possibly if the new firmware was installed then there wouldn't have been a problem.  When the P4 first came out there where a number of incidents with gimbal guards, more recently the problem appears to have been more or less solved so I was surprised to see this.

We haven't seen any images of the damage, maybe it can be repaired?

OK
So, if the new update was in there, this "landing protection" would have somehow known or mitigated a false indication of having landed by a gimbal guard...correct?
If that is right, how does it do that?
Thanks!

As far as I can tell, it looks like i'm running the latest firmware so it looks like we're back to square one.